Effects of Synoptic Surveillance on model forecasts for
09 September 2004 0000 UTC
Ivan.


Quicktime movie of AVN DLM wind model forecast
Quicktime movie of DLM wind data increment


TRACK AND INTENSITY PERFORMANCE

TRACK (km)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN 64 70 91164286354562663752873
AVNO 46 91202211244290421575730904
%IMP28%-30%-122%-29%15%18%25%13% 3%-4%
GFNO 70157257259311367435578766944
GFDL 78179304285322355437610804996
%IMP-11% -14% -18%-10%-4% 3% 0%-6%-5%-6%
INTENSITY (kt)
MODEL12 h24 h36 h48 h60 h72 h84 h96 h108 h120 h
AVNN-100-89-85-91-80-104-82-94-94-94
AVNO-85-72-70-85-75-97-87-90-89-88
%IMP16%19%18% 7% 6% 7%-6% 4% 5% 6%
GFNO-18 5 2-15-11-48-44-45-49-52
GFDL-14 -2 -4-27-15-48-44-45-49-50
%IMP22%60%-100%-80%-36% 0% 0% 0% 0% 4%

Landfall forecasts

11/0330 UTC 17.4N 77.2W 20 n mi S of Portland Point, Jamaica 51.5 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 18.9676.29 66.0198.2Offshore Annotto Bay, Jamaica
AVNO18.7275.86 42.0203.8Near Buff Bay, Jamaica
%IMP 34% -3%
GFNO18.1674.61 33.5286.7Grosse Chaudiere, Haiti
GFDL18.2974.49 32.0303.2Carcasse, Haiti
%IMP -8% -6%
12/1415 UTC 18.9N 81.5W 22 n mi SSW of Georgetown, Grand Cayman Island 86.25 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 19.9876.32 78.0555.8Bellaire, Santiago de Cuba, Cuba
AVNO19.8277.73 60.5408.2Near Niquero, Granma, Cuba
%IMP -212% 27%
GFNO19.8677.41 51.5441.7Near Niquero, Granma, Cuba
GFDL19.8977.30 49.5453.7Niquero, Granma, Cuba
%IMP -6% -3%
14/0100 UTC 21.7N 85.2W 15 n mi SW of Cabo San Antonio, Cuba 121.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNN 20.0076.10 84.0963.5Santiago de Cuba, Santiago de Cuba, Cuba
AVNO21.2978.47 80.5697.2Vertientes, Camaguey, Cuba
%IMP -48% -14%
GFNO22.1180.43 78.5493.8Cienfuegos, Cienfuegos, Cuba
GFDL22.1480.36 79.5501.2Cienfuegos, Cienfuegos, Cuba
%IMP 5% -12%
16/0650 UTC 30.2N 87.9W Near Pine Beach, AL 175.0 h into the forecast
MODELLATLONTIMEERRORLOCATION
AVNNNo landfall forecast
AVNONo landfall forecast
%IMP
GFNO25.1980.88100.0887.0Plantation Key, FL
GFDL25.2480.60 99.5905.0Key Largo, FL
%IMP 12% 0%

Figure 1. NCEP 850 - 200 hPa mean wind analysis for 09 September 2004 0000 UTC (Hurricane Ivan).

Figure 2. Track forecasts for the no dropwindsonde (NO or NN) and the all dropwindsonde (AL) runs for the AVN and GFDL models initialized on 09 September 2004 0000 UTC.

Figure 3. NCEP Global Ensemble Predction System track forecasts for all cyclones in the Atlantic basin initialized from 07 september 2004 0600 UTC to 08 September 2004 0000 UTC, showing the tracks of Hurricane Ivan.

Figure 4. Ensemble perturbation variance at the nominal sampling time 09 September 2004 0000 UTC from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.

Figure 5. Variance explained within the verification region (large red circle) for observations taken at the sampling time 09 September 2004 0000 UTC from the Ensemble Transform Kalman Filter run from the previous day NCEP ensemble forecast. The green circles represent the dropwindsonde locations.

Figure 6. Initial condition differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 09 September 2004 0000 UTC. The circles represent the dropwindsonde locations.

Figure 7. 24-h forecast differences in the 850 - 200 hPa mean wind between the no and all dropwindsonde cases for 09 September 2004 0000 UTC.